Combustion system

ABSTRACT

A combustion system includes: a furnace housing defining a combustion chamber therein and having a gas outlet in fluid communication with the combustion chamber; a plenum housing surrounding and cooperating with the furnace housing to define a plenum chamber therebetween, and having an air inlet and an air outlet which are in fluid communication with the plenum chamber; and a heat exchanger housing disposed outwardly of the plenum housing and having an air inlet in fluid communication with the air outlet of the plenum housing, an air outlet, a gas inlet in fluid communication with the gas outlet of the furnace housing, and a gas outlet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a combustion system, more particularly to a combustion system including a heat exchanger separated from a furnace.

2. Description of Related Art

U.S. Pat. No. 4,449,510 discloses a heat exchanger furnace that includes a furnace housing defining a combustion chamber therein, a plenum housing surrounding and cooperating with the furnace housing to define a plenum chamber therebetween, and a number of exhaust tubes disposed in the plenum chamber. A combustion gas from the combustion chamber of the furnace housing flows through the exhaust tubes along a serpentine path and into a stack. Meanwhile, ambient air passes into the plenum chamber, and is heated by contacting heat transfer surfaces of the combustion chamber and the exhaust tubes. However, the heat exchanger furnace thus arranged, i.e., the plenum chamber surrounds the furnace housing and the exhaust tubes are disposed within the plenum chamber, has a relatively poor heat exchanging efficiency between the exhaust gas and the heat exchanging air.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a combustion system that can overcome the aforesaid drawback associated with the prior art.

According to the present invention, a combustion system comprises: a furnace including a furnace housing defining a combustion chamber therein and having a gas outlet in fluid communication with the combustion chamber; a plenum housing surrounding and cooperating with the furnace housing to define a plenum chamber therebetween, and having an air inlet and an air outlet which are in fluid communication with the plenum chamber; and a heat exchanger having a heat exchanger housing disposed outwardly of the plenum housing, defining a heat exchanger chamber, and having an air inlet in fluid communication with the air outlet of the plenum housing, an air outlet, a gas inlet in fluid communication with the gas outlet of the furnace housing, and a gas outlet. The heat exchanger further has a tube-bundled structure disposed in the heat exchanger chamber and defining a plurality of passageways extending between and permitting fluid communication between the gas inlet and the gas outlet of the heat exchanger housing.

BRIEF DESCRIPTION OF THE DRAWING

In a drawing which illustrate an embodiment of the invention,

FIG. 1 is a schematic view of a combustion system embodying this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates the preferred embodiment of a combustion system according to this invention for combustion of solid waste, such as hull or shell waste of agricultural crops.

The combustion system includes: a furnace 10 including a furnace housing 11 defining a combustion chamber 111 therein and having a gas outlet 112 in fluid communication with the combustion chamber 111; a plenum housing 61 surrounding and cooperating with the furnace housing 11 to define a plenum chamber 601 therebetween, and having an air inlet 611 and an air outlet 603 which are in fluid communication with the plenum chamber 601; and a heat exchanger 50 having a heat exchanger housing 51 disposed outwardly of the plenum housing 61, defining a heat exchanger chamber 511, and having an air inlet 501 in fluid communication with the air outlet 603 of the plenum housing 61, an air outlet 502, a gas inlet 503 in fluid communication with the gas outlet 112 of the furnace housing 11, a gas outlet 504. The heat exchanger 50 further has a tube-bundled structure 3 disposed in the heat exchanger chamber 511 and having a plurality of exhaust tubes 31 which define a plurality of passageways 30 extending between and permitting fluid communication between the gas inlet 503 and the gas outlet 504 of the heat exchanger housing 51.

The heat exchanger 50 further has a plurality of baffles 64 dividing the heat exchanger chamber 511 into a plurality of sections 5111 which are connected to form a tortuous path extending between the air inlet 501 and the air outlet 502 of the heat exchanger housing 51.

A manifold 22 interconnects the gas outlet 112 of the furnace housing 11 and the gas inlet 503 of the heat exchanger housing 51, and extends through the air inlet 611 of the plenum housing 61.

During combustion of the solid waste, the combustion gas generated from the combustion chamber 111 passes through the manifold 22 and into the exhaust tubes 31 of the tube-bundled structure 3 and then into a cyclone 23 connected to the gas outlet 504 of the heat exchanger housing 51 and finally into a stack 8 connected to the cyclone 23 for emission of the combustion gas. Meanwhile, an air blower 242 is disposed downstream of the air outlet 502 of the heat exchanger housing 51 for introducing ambient fresh air via the air inlet 611 of the plenum housing 61 into the plenum chamber 601. The introduced air flows around the furnace housing 11 for conducting a preliminary heat exchange, and then flows into the heat exchanger chamber 511 in a sinuous path across the exhaust tubes 31 of the tube-bundled structure 3 for conducting a primary heat exchange. The heated air is then delivered into a crop dryer 7 for drying crops stored therein.

By disposing the heat exchanger 50 outwardly of the plenum housing 61 of the combustion system of this invention, the heat exchanging efficiency between the introduced air and the exhaust gas can be considerably improved as compared to the aforesaid conventional heat exchanger furnace.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1-3. (canceled)
 4. A combustion system comprising: a furnace defining a combustion chamber that has a gas outlet disposed at a top end of said combustion chamber; a plenum housing defining a plenum chamber that receives said combustion chamber and that has a top end extending above said top end of said combustion chamber, a bottom end extending below said combustion chamber, an air inlet provided in a space between said top end of said combustion chamber and said top end of said plenum chamber and having an open end adapted for communication with ambient air, and an air outlet proximate to said bottom end of said plenum chamber; a heat exchanger defining a heat exchanger chamber disposed on one side of said combustion chamber and having a top end lower than said top end of said plenum chamber, an air inlet disposed in one side of said heat exchanger chamber proximate to said combustion chamber and communicated fluidly with said air outlet of said plenum chamber, an air outlet proximate to said top end of said heat exchanger chamber and disposed in the other side of said heat exchanger chamber opposite to said combustion chamber, and a gas inlet and a gas outlet both of which are disposed at said top end of said heat exchanger chamber, said heat exchanger chamber further having a tube-bundled structure disposed in said heat exchanger chamber and having a plurality of exhaust tubes each of which defines a passageway that connects to and that extends downward from said gas inlet of said heat exchanger chamber and turns upward at a bottom end of said heat exchanger chamber to connect to said gas outlet of said heat exchanger chamber; and a manifold extending above said combustion chamber and said heat exchanger chamber, and extending through said air inlet of said plenum chamber, said manifold having one end connected to said gas outlet of said combustion chamber and the other end extending through said open end of said air inlet of said plenum chamber and connected to said gas inlet of said heat exchanger chamber.
 5. The combustion system of claim 4, wherein said heat exchanger further has a plurality of baffles dividing said heat exchanger chamber into a plurality of sections which are connected to form a tortuous path extending between said air inlet and said air outlet of said heat exchanger chamber. 